In studies using different bone densitometric techniques for measurements of changes in bone mineral of the proximal tibia after primary TKA a significant decrease in BMD is seen in most studies (Hvid et al. 1988, Karbowski et al. 1999, Levitz et al. 1995, Petersen et al. 1995, Regnér et al. 1999). In some of the studies the decrease in BMD reaches 20% - 36% (Hvid et al. 1988, Levitz et al. 1995, Petersen et al. 1995, Regnér et al. 1999), however, in other studies BMD remains unchaged (Bohr & Lund 1987, Li & Nilsson 2000, Spittlehouse et al. 1999) or shows a minor increase (Petersen et al. 2005).